Anton/sync groups and verticals

This fixes https://openedx.atlassian.net/browse/BLD-1095

NB: before merge `ENABLE_GROUP_CONFIGURATIONS` should be set to default value.

Please review: @tymofij  @cahrens 
re second place: I mean that you're relying on the name being stored both on the vertical and in the user partition table.

re display_name being changed: I my suspicion is that calling `get_module` would probably reset it, but I'd be surprised if anything else was reverting it.